Spark plug cover



y 1965 R. w. CASEY 3,181,523

SPARK PLUG COVER Filed NOV. ].9, 1963 INVENTOR F0 5527- VV. 64555/ A 7"TOE/YE Y United States Patent 3,181,523 SPARK PLUG COVER Robert W.Casey, 2362 N. 49th St, Milwaukee, Wis. Filed Nov. 19, 1963, Ser. No.324,680 2 Claims. (Cl. 123-198) This invention relates to a cover for aspark plug of an internal combustion engine.

Many internal combustion engine powered devices commonly found aroundthe home, such as lawn mowers and snow blowers, are not provided with anignition lock or other device for preventing operation of the engine.This presents a hazard to children who may be inclined to tamper withthe device and either accidently or intentionally start the engine andinjure themselves on one of the moving parts.

The primary object of this invention is to provide a cover for a sparkplug from which the ignition lead has been disconnected which may belocked to prevent operation of the engine. Another object of theinvention is to provide such a cover which is effective and yet simpleand economical to manufacture.

In the present invention the cover is comprised of two parts. One partis at all times secured to the cylinder head by the spark plug and theother is removably engageable with the first part. Finally means areprovided to permit the two parts to be locked in engagement with eachother.

The invention is illustrated in a preferred embodiment in theaccompanying drawing in which:

FIG. 1 is a fragmentary side elevation of an internal combustion engineshowing both parts of the spark plug cover in place and locked inengagement with a padlock.

FIG. 2 is an enlarged portion in section of the spark plug, both partsof the cover and padlock as shown in FIG. 1.

FIG. 3 is a view similar to FIG. 2 showing the padlock and removablecover part removed and the ignition lead connected for normal operationof the engine.

FIG. 4 is a perspective view of the two parts of the spark plug cover inspaced relation with a portion of the cover part normally secured to thecylinder head broken away.

Referring to the drawings, a spark plug 1 is threaded into the cylinderhead 2 of an internal combustion engine 3. The ignition lead 4 isconnected to the spark plug 1 during operation of the engine 3. Disposedbetween the spark plug 1 and the cylinder head 2 is a gasket 5 and afirst cover part 6. The first cover part 6 is of generally tubularshape, having an axially extending, circumferentially continuous sidewall portion 7 and an end portion 8 at one end in which an opening isprovided through which the threaded base portion of the spark plug 1passes. Also associated with the first cover part 6 is a transverse,outwardly extending member 9 which has an opening 10 therein. The secondcover part 11 is of tubular shape having an axially extending,circumferentially continuous side wall portion 12 and one closed endportion 13 and a transverse, outwardly extending member 14 with anopening 15 therein. The side wall portion 12 of the second cover part 11is adapted to slidingly engage the side wall portion 7 of the firstcover part 6 after the ignition lead 4 has been disconnected from thespark plug 1. Once the side wall portions 7 and 12 of the cover parts 6and 11 have been engaged, the transverse members 9 and 14 are adapted tobe positioned with their respective openings 16 and 15 in alignment topermit the staple 16 of a padlock 17 to be passed through said openings1d and 15 so as to lock the cover parts 6 and 11 in mutual engagement.

The cover parts 6 and 11 may be made of any relatively non-resilientmaterial. The cover part 6 must be capable of withstanding thetemperatures achieved by the cylinder head 2 and spark plug 1 duringoperation of the engine. Steel had been found to be a particularlysuitable material for both cover parts 6 and 11.

In the embodiment of the invention shown in the accompanying drawinglimited axial movement of the cover part 11 with respect to the coverpart 6 is possible with the padlock 17 in locking position. Thus, thecover parts 6 and 11 must engage each other a sufi'icient depth andtheir mutually engaging side wall portions 7 and 12,

respectively, must be of sufiiciently close tolerances so as not topermit the cover part 11 to be pried oil the cover part 6. Otherembodiments of the invention are possible which will reduce'or preventthis limited relative axial movement of the cover parts 6 and 11 when inlocked position, as will appear to those skilled in the art. Forexample, simply disposing the transverse members 9 and 14 in a planeincluding the axis of the cover parts 6 and 11 will greatly reduce theamount of possible relative axial movement of the cover parts 6 and 11when the padlock 17 is in locking position.

It should be noticed in the embodiment of the invention shown in theaccompanying drawing that the side wall portion '7 of the cover part 6adjacent the cylinder head 2 is of reduced diameter. This is not alwaysnecessary depending upon the dimensions of the spark plug 1 and thecylinder head 2. There should be sutficient clearance between the sidewall portion 7 of the cover part 6 and the spark plug 1 to permit theuse of a standard spark plug wrench to tighten the spark plug 1.Otherwise, the side wall portion 7 of the cover part 6 may be of anysuitable shape which will allow clearance between it and the spark plug1 and cylinder head 2.

Also, in the embodiment shown the transverse members 9 and 14 areintegral with the cover parts 6 and 11, respectively. The transversemembers 8 and 12 may be formed from separate pieces which may be securedto the side wall portions 7 and 12 of the cover parts 6 and 11,respectively, by any suitable means such as by rivets or other fastenersor by welding or brazing.

Since many possible embodiments may be made in the invention and manychanges might be made in the embodiment herein shown and described, aswill appear to those skilled in the art, it is to be understood that theforegoing is to be interpreted as illustrative and not in a limitingsense.

What I claim is:

1. A cover for a spark plug of an internal combustion engine from whichspark plug the ignition lead has been disconnected comprising first andsecond slidingly engageable tubular cover parts; said first tubularcover part being the one of smaller diameter and extending less than thenormally exposed length of said spark plug and having a relatively fiattransverse member extending outwardly from the medial portion thereofand an end portion at one end thereof, said end portion having a centralaperture therein slightly larger than the outer diameter of the threadedbase portion of said spark plug whereby said first tubular cover partmay be secured to the cylinder head of said internal combustion engineby said spark plug; said second tubular cover part being closed at oneend and having a relatively flat transverse member extending outwardlyadjacent the other end thereof; said transverse members being disposedin planes normal to the axes of said first and second tubular coverparts and having aligned openings therein through which may be passedthe staple of a padlock thereby preventing substantial relative axialmovement of the engaged said first and second tubular cover parts.

2. A cover for a spark plug of an internal combustion engine from whichspark plug the ignition lead has been 3 disconnected comprising a firstcover part and a second cover part; said first cover part having anaxially extending, continuous side Wall portion and an end portion atone end with an opening therein slightly larger than the outer diameterof the threaded base portion of said spark plug; said second cover parthaving an axially extending, continuous side wall portion and one closedend portion; said side Wall portions of said first and second coverpar-ts being slidingly engageable; and locking means for preventingsubstantial relative axial movement of the engaged side Wall portions ofsaid first and second cover parts comprising at least one pair oftransverse, out- References Cited by the Examiner V UNITED STATESPATENTS 1,353,959 9/20 Holst 123-146.5 1,511,001 10/24 Padden l231982/39 Meredith 123169.1

FRED E. ENGELTHALER, Primary Examiner.

1. A COVER FOR A SPARK PLUG OF AN INTERNAL COMBUSTION ENGINE FROM WHICHSPARK PLUG THE IGNITION LEAD HAS BEEN DISCONNECTED COMPRISING FIRST ANDSECOND SLIDINGLY ENGAGEABLE TUBULAR COVER PARTS; SAID FIRST TUBULARCOVER PART BEING THE ONE OF SMALLER DIAMETER AND EXTENDING LESS THAN THENORMALLY EXPOSED LENGTH OF SAID SPARK PLUG AND HAVING A RELATIVELY FLATTRANSVERSE MEMBER EXTENDING OUTWARDLY FROM THE MEDIAL PORTION THEREOFAND AN END PORTION AT ONE END THEREOF, SAID END PORTION HAVING A CENTRALAPERTURE THEREIN SLIGHTLY LARGER THAN THE OUTER DIAMETER OF THE THREADEDBASE PORTION OF SAID SPARK PLUG WHEREBY SAID FIRST TUBULAR COVER PARTMAY BE SECURED TO THE CYLINDER HEAD OF SAID INTERNAL COMBUSTION ENGINEBY SAID SPARK PLUG; SAID SECOND TUBULAR COVER PART BEING CLOSED AT ONEEND AND HAVING A RELATIVELY FLAT TRANSVERSE MEMBER EXTENDING OUTWARDLYADJACENT THE OTHER END THEREOF; SAID TRANSVERSE MEMBERS BEING DISPOSEDIN PLANES NORMAL TO THE AXES OF SAID FIRST AND SECOND TUBULAR COVERPARTS AND HAVING ALIGNED OPENINGS THEREIN THROUGH WHICH MAY BE PASSEDTHE STAPLE OF A PADLOCK THEREBY PREVENTING SUBSTANTIAL RELATIVE AXIALMOVEMENT OF THE ENGAGED SAID FIRST AND SECOND TUBULAR COVER PARTS.